This part of ISO 10303 provides general and application-independent means of representing structured and unstructured meshes, and mathematical functions and numeric data defined over such meshes. The schemas in this document are specified in the EXPRESS language; EXPRESS is defined in ISO 10303-11.The following are within the scope of this part of ISO 10303:— mesh-based topologies; — cell connectivity and multiblock mesh interfaces; — mathematical functions defined over meshes; — the association of numeric data with the cells, faces, edges, and vertices of a mesh.The following are outside the scope of this part of ISO 10303: — applications of mesh topologies; — applications of mesh interfaces; — the semantics of data associated with a mesh.